SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f730837bf3bba1e3976bbc47b23a884f79368d68f0fe8bb401c85269a308745d' 
  AND token = 'g4rQlzuIt6AD77QjKhZ3ITxpQp0dN5eobA9vEwR7GhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}