SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '733922fb51947df57d8585f4b79c2276aeb82e68860e69528a3e876c78be7437' 
  AND token = 'XMoDn6l+wiFZ8nCz9LRq+CbCJwgSov14hHbSBBi1hKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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