SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0362773e42896238bef9caeefc1387df267ccaf3055fde7827f91cf06191fdcb' 
  AND token = '+9wkizyooXbEXfe0AXjBKBntjC2kKAinhUVSgPylztc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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