SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1af2446afd0ea47443664a47750ddfd83892282d1c7d9dfbe9caf39d1b8abb3' 
  AND token = 'JxN93up+vhjwJSpSbxUIO5LcSU3LdvQBqdB5sqPwlXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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