SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d909ffaf232230a4b8ec735654cf5cafcf55d5773867a94d2450279f6099a5a' 
  AND token = 'sylLrOAIyhpSPVtknjZuPBxgGJJ76CWd2UALrjykCZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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