SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '091c0eb5bd82668831670d0388c7da0b06051d1d9cdb18ed089702b728382a36' 
  AND token = 'KMQY0cCZ6m47j7uLxMddbbxDbbuMcLw/OPjLCs6fSmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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