SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b539f7e4dc028624348e2a2fb8707200d32c46eedfaf3d712c83a5063f316e3' 
  AND token = 'wfBH8wzG149rNAgfmti0nY996f9dbsXAeYm6Pt5UwmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}