SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b54ca8b9266fd8309fb3ddf4843208b4f0829bb0093aae6506ede03579679eb6' 
  AND token = '9HZzD9pLjP06q/h0ebFz5dAaTaSTv8xHJ0zzFfmumiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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