SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39cfd84dcddad56d888ece94612ca8babea71023abca09f8f9923eb8c30787cd' 
  AND token = 'MtlH0ZXbBt23E1yAm+tN4iN/lSVrczV2z9X4MlgSGCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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