SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6898fddb3184e1eaaee026cc469c5570f47a1cfc95cdd92bab37e20ed28d2468' 
  AND token = 'MCYtc4NRPVOqn8MRKNhfs0i4N1py3jC6skCO78XK70s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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