SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2758f9d581ac7b99cb14aba515c74821e5f5da91cf99fa0d93e4bf2466a6e96' 
  AND token = 'zPU7Q3ccnsqjRieZf5ZAy7AJCx1foFvdjHQKIC2/EHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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