SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b845495cf4057a44fb09b1602373f397a24c73cccd4caede46801f90e98f83b' 
  AND token = 'V2riNivdERjBdDCNtb6R5cROa1ikshbduL3/YcqYSUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}