SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b218e8123f22db35e9e97713218909cbf2e1978759edbb453d17f11dce9e99e1' 
  AND token = 'sIMJ29eUFlMiwLWYeIUX5pfVz+WtNYk1odlxQl/sRWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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