SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bd73aaade55752c1b0aba7766b47bbf7007f607230229ebcf3cb0d1c5424989' 
  AND token = 'K964VvKd5TNB5Y0iicqbYiCD4fvAWv2d1g1Yl9+jXzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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