SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd84875e0ad46821b8a9749b65a6f43b0945d2907760c61544b6608c1b268e190' 
  AND token = 'HfyBI7xet5tKlS5XFMyQ2b1o0fMXk2XYsgx2WVABaE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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