SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb42581b9dae0b4f7466866f43b4c74393ab54aadf82bc6d49365a55f965bdd2' 
  AND token = 'wWm995Qmkj9rWMgbQ1hQaFDtPlEvr9S8UtjrYsFNcdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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