SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3b945643d0775986300912db51c16fc8e2d7b820cb6d4b207092ec21e61ad9' 
  AND token = 'loiPhmszbSR9tE73lcDLZ8irrNAOB9bCHQqyJIzvL5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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