SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4e045701b938eb78afdf164688fc7d967272e3884d6796deaa59b242de7943' 
  AND token = 'rDAKiEao6eeCYGKhu/ryk9xJ2cjuuBjR+VE5QqvsSxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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