SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1308fac5fecd231d81bbcb5a2438d95db487f3f0513085fc211681ddcc42b64c' 
  AND token = 'GDmVbDlwZaFY+j+AbJGMNXP0gfPnXOyDymc44Tqm0xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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