SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0db3d588bb2cfd60a1a0482e6f4b154458a20999dff46461a76a161f676715f8' 
  AND token = 'kKPqvam6fyBN4T4ZYyYv26Cbjd4lmlQGhgUNWFHfWM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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