SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '115046dc5d61dd6b7987225891aefe573120d8458a0b69bc64b45ea5b3c6e50b' 
  AND token = 'LXXRz1P10laCcIQjcaPtSBYberFHVYo4bYcbHirDrZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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