SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a02bbd3e93e2d4539e206655d013bedd1a197de22de5b7c29c8f01e8363a09a' 
  AND token = 'xq+mRsf88mLPvKwMGK3SroZB78CRSLj/6/zQvKxBWUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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