SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9cdc430793b13254c5229ae10b363598604f63caa17f0c2e852481f8abd5d1' 
  AND token = 'YMeMQmhI1umsFkJvGhBeYijM1nw5DFprDXavmgKvLUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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