SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45df818e27f51871694de6399c363b37683c5fa85fa2336cd1c365296b380241' 
  AND token = 'm7JoO8Lw+Hvbs5+k8655qMj1WSpyf6Yer4TINlJHmqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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