SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d71ce0d686c9830f0662ecaba70640b2bbd78520686e327772b64871cc7ee43' 
  AND token = 'jK+lh9SWlbvCXxV1iUaai+CsnPmPagxbQuEPjlqW6v0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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