SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f6ea9bea287155ad6ab130a1d2efe0e6349f2edf7d5320ffda7a431e43cd92e4' 
  AND token = 'JQv6L+jbYMwCB1/b096OVUcVTnwSWiKf0nzcs5sYmyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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