SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5f3f1851d7cd42b2a644587e4f4275246d3be1d2efefc1cef2d9360c74663147' 
  AND token = '5yHCcj8xYAglLEr4GiW5PyhSBzHvutk2g+OZ0PKEoYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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