SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5315a0fba268aee545bda97bb0b6e42387235339ca2e1cd0fc4f52e844eefe5' 
  AND token = 'AfUS94H+rl44FWQzAXDPllhfPCwoumZK8WGr5wkh/1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}