SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b88323ad4faf99e75dc2d03be5023d4d1f83cbc2325369e13ed42a5efc955357' 
  AND token = 'FBYwt19oUMkKCmUoTptFaH77ZV104YKV6mO7+/qxW/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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