SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76710325f34cbe263363fcb01d7d02aca23017a505a47712cc19595861371c61' 
  AND token = 'Udl1jIJkyt+hczyaKb8TOIppsybaItstOvuobg3aGm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}