SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '782f322463e66d62175b07b45725582eb1942dc008648380cf2896686e6f0b7c' 
  AND token = 'YKnxQ+8GBc+2VZh/a29ukzu3MmwX7iJuU5KcC3yrOGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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