SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd685ce2d292e47df38ee05211d27d446c0f82d3270274366f64ee90a82af0048' 
  AND token = 'JKSWEnvMNohnKsikFYzBfIgAvn4e+M0QmHlc9V/oNtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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