SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d703280d6b8f32015b333d195b10d24aeb5f4d626da202c90b7e12a72d87d52' 
  AND token = 'EZxwQIRNIXOzCE/QkEklDZ4P8rJlZF/RBMB/MfMja+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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