SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2271d67e878374991055830931afd2b93724769b18682f651f7e961904f5d8b4' 
  AND token = 'Ugu/gt54vPtlPjesKVtDM8+VOh2HqrvtKs3PF3iGtRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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