SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e91833004b09d37338eaf694c92e8b0fdf5eeb6ecfaf5dd21616dea5f6c4d056' 
  AND token = 'WjUDeH1uA/xOoWDtggApxS1xj2hEYjDajGfivpJRQVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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