SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87fe160c5ea0b0c2ac7af062d743fafcfb472f00cba272e23b2ab7ceac566533' 
  AND token = 'kQbLT5SLOrm/TM++xtGEoSyVAUuER6waePfVrfWVguA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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