SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '38e8073aba2797d1eb4e25b2833d98222d836589c7561be654c58a2bc6d82bad' 
  AND token = '3GKuW748DieeoFW2h3FUfhjSsdeUaxve/m/RDdPChfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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