SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd62198836eb1b4230cc3903ac58932329b7adbcd1589767f6508c181e0ca5dd8' 
  AND token = 'nWylrkga05jfp9/7UpwSvlsJpatmwkMDy8NqBMOVtNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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