SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f1b68853498ad58c975cf3cc1e95a55ee51959225c1b783a71aa90fd77e648' 
  AND token = '7e4eBbBFjHa5y8cL23OaafqzixXW/kS50+ocVG7XD7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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