SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ba00c087a435e09cb8d4e222307c488e970c5a2063f88d5b1ea49e3276b11d7' 
  AND token = 'K/5g2XXuzTld/SgTVzOnbjGL6+FdvYNzEoM/yd7t6wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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