SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '48b384d5ce03376f365923dec12fe297b20e01298c79f001978504d47a97239a' 
  AND token = 'CWhufjeHl2fqVDVvksMb0OwYupv/Hwr02c3kGei4MFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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