SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81cb4d1df4244c03973fdaac4f15a0a5e87fb5db55077ac91ed82bc6e334d1a2' 
  AND token = 'TjWLSBi7Uimn3gMEQBU67xSQNMViO/NbQqQjRqRD2to=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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