SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '75e34501872fd9753b083cf4bfdd6da51225de7a4f8530211a18014975d9999d' 
  AND token = 'tlfFXuvWX6Qa0hBkVm2mpzY9LgMS8ogSLpQJf4DMtGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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