SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3e5257a0f7c25bce95ad3795141323c3b39dce9cf8fa7ba8577be4056572806' 
  AND token = 'Lg/f8k9vbHMYcYxhHQCjwUzI/r6Tds12AkzcJKkqDcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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