SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c432ac4a2f5da263700126c40fd6437e5b9cf3f00eea9ca6652ea72b471fc45f' 
  AND token = '3gcRfmc/YxKhYd1swu/emP3tgklEKkNgFbknSOjGVz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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