SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bcb33dd864ce84955f4b7c9e9f897709c854c3057238ee3b3d8988f44d12156' 
  AND token = 'ch1RfkpDNH39DJTp8aCryrDcnT+aoD1sLGEfTfq/YX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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