SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b9471d316c6e8a6566c3aac89a0fc88345cc0d6de9770065f8ba105ef66fd1e' 
  AND token = 'eJBiD1T4HKrsKaoNW4wmgBGh3vU/DEXfdKajxtxa+Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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