SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f98431d60fab22fe8eaa3fc1f1bf17670ab5952faccd74ddd6d25aef80798241' 
  AND token = 'ldhec7vMLUkSZ367ZhWxHI/8WknGZZ9sMHqbNWGMoIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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