SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd968729050f3a37ec2d82d3b6daa8d4c4535b472a456bc6ff9e28449110c4667' 
  AND token = 'qZcy2mA0Rca2HYPuFMwFugmc2WtASVP/vcStBKlKgJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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