SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ca184357588a602029f291c3cc584c9899c779e88940055933a412a7e77d34' 
  AND token = 'gHntTkftkuvUKj2lPdrMBe96PkVRGqMbDX9AaLOJOGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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