SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a5b6446f9dc7c83c90a11fb009654375755fadc1b3246090f10ffbd6bae4cf9' 
  AND token = 'cxj0aEDirOKw+BkWr/gGQmC6l1TI+NwdhCgnptvIOVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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