SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f948fc66793dadd075a816c63484611beafb95d4d765f1264b27c6f87b8a0af0' 
  AND token = '6LUif8XjfpQEOOJTti/915qB1uOyRk6tvkcsIHsxXu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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