SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15ce88a695911791daf33a8bf6bba5b30ef1f4dc64d98439111136219f9a2778' 
  AND token = 'VCWew0VjRb7fgdtTRvmDnay9RIZC+Nwj4ieD6hkRdCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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