SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8f3262c30f5a6fb9727afa9ca726785169f8b59af22fde42c495f72edfa64558' 
  AND token = '/wE1vF+6PTu3+qj/Gjdpbjw8dnep/IC2Vm+tUDWIzT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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