SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '651b1174758534d5d15904a41264164d6556aaf831a01d7a1fed3a977328c86e' 
  AND token = '2blEYwhLkFIphrnyqlPe1f5kPQtwMqGw6XxdEKD9Q2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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