SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a1d3bc1e8a49a4db56325f199eb3f961e4651c535cf549f97739043cd7dedf9' 
  AND token = 'kIZZNYzUCFLdQTt5ywtdDsF8MsD+QSV5N85k74k6SNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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