SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39365f1feb939befc4184704387618ce229acc7e376e832340ff52e9590bd6ff' 
  AND token = 'KztodXRHIlc2T8iPxpGj+U/nA4ydkQumPnVwFYnY0IU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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