SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d62a95de05746ba9535e6b55f783d41cf108cb973d59f57a8083bcbbf74a249' 
  AND token = 'GTRRW8S0irF4XatCFhm8LdXwEfc+R7nXETDVVGLMg1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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