SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '151c35e40d143f9ae3446edea726b042fe0b74c5e5909b22def24ed81f44ea32' 
  AND token = 'CQ8SN+uBVud1RSZR9aCs5Fmox/HaWN5su7q0dNXhFSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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