SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd90f33a0791130414a0222b82f39c37ee02295d48036eb400b1db7aea2bae3c6' 
  AND token = '/GTgyrfvzvwdU0WbGrDK54qdSyQOXM5IrMSjUFLtEFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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