SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7fa7dd9312e0ef5501e1cae929a399107eb4649d7aaa916cc747a6acee93c10' 
  AND token = 'P/iymhpDPa/bPRIp6PgDYjyz1m8k9C4MKxs/WJhB02Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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