SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '402983abc9d1f17445d9b36c7f219f9cbcbf5a969d8008dad9a178598edf7e65' 
  AND token = '2j0FQ6jYJTNdHyLHmZXOpZWpvS3QB6f2+L8MlOtV6+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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