SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f18914768d76ee70a59af771901b095a099cbbc4f3f5dc112e8c4d82468c5f4e' 
  AND token = 'LdyGQRKL1cQ7oX+BhOCWKHyhV2gXV1VxR+h42WJzlH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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