SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd23cc68f1f025931f7a78a979be55106aac69a4b5d17a9073b84b73dfdb620d3' 
  AND token = 'J0ywZ/KN9UUfVL/E4ZOx1UZ3zG5f+B9QuR+nHqlMyD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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