SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f779916ca0af25b8b8b5e3aefe20cade31d105372521c7eb8f425f4ab6d1991c' 
  AND token = '4zsjkm6KsuPxb+o3H2BW6tf/UvoLCdI7wzQ4j1ncyhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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