SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73db47e5a7a98d43b9d4ddcaa246d14768aabc837ea2e4833847960aaecac8b4' 
  AND token = 'wnAvhSLJFIQ46MkDQ8CgO1WXFcp5X0fDtPK4LaZDlgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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