SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84ff8858e946075b52c48e030bf1b150a87a29297dc60d2e992167c4043ee499' 
  AND token = '0jVvCgtn8m4DHEXG55CppXoX1iZgUalVdSMOANtIO9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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