SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '344505149e71b4a3a7ea370cf89eba701e2839ea9494538aa3c7fc8c6e53e67a' 
  AND token = 'SurcYjTpxMng3IsfFo7oYSpS4zZmrJNQKHgcbxNdoyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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