SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11b3f9ba1cf182d9a7bb4ec4cd198911758c8488e46533aaa502dde4a911bec' 
  AND token = 'R10PTNX+mWWuwYnLDvhKyJGnIvvXwGBzvGA0wqhsRZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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