SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3221c21556f6c0c3d0d52745a1d93a8e454da187eba28fea607f33df9630d4b0' 
  AND token = 'ZvHkAMZGbHcM6uqBGgh6U/mSTJDeebid4vqIvpKlI64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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