SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '676177d9dfa4a43f018a5eb8f6a940cf428bcee9263fc53eaebeae8aff88a151' 
  AND token = 'kpmWVMOmmBFHga16oz2Hl4R+ftEpypO4AhFof1AC25U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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