SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8baac09370263cb1c5b173695225c86c620db8fa2c7081c226423f9b823b12cb' 
  AND token = 'iu1C8O9aMlvNEVazbo+tLDt+BM2Ozh4N0f5UsOSwz8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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