SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90c549120a32acb15023d231f4babf4df34371a8e9c228cdee8b860405e001ca' 
  AND token = 'x9LJQazk/V7vGFHPqGDNd5Rr3SBzgidbTgrFJcGBfzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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