SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7284fe076136595f55b476d5b63fb88d4f7e3c631297dde48c617f92083e655' 
  AND token = 'NFS+c/UUcVm7QNBOcSzgDWXtIlIPsyZ2SAIReWZnzIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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