SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28849bc560d2b5d8300ccdafd227f71ec6192a0755021b81cae4dd9fe867e3a2' 
  AND token = '4LoHcJDwzuuvdMNoSUzRHwCskW24b3TpErVoYgkfSUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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