SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af78c47883b4363d950466c8518d0959618e429a5ba0c797207fcdf4b7b28c36' 
  AND token = 'Cgf6weCS6BWUoHJNXtloR6HAuiEFD2omtVXnQLX0L58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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