SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25ccf69baa751c97065faa588561b89a63494661aa993c257bb0e9b2e07d931e' 
  AND token = 'Cxiaj0KatPLgfiAU/82Ka6I1Wzy2k/m0ul/YLt3JRbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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