SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '795903f5beee5f3ea79f8099b675c969a9cdd0d16ac62bf3ec617ae917a6028c' 
  AND token = '29NLhkAWm3hOUz/+E9NU4vScAVWv1DJuJD3XA9Kfaek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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