SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d331e421cee4489963745d9fcc23271326e561003ecee6fe60d20cbb109b968' 
  AND token = '+p5Hj4fuR0nRYRCdmkDMK/MPgLX4nzqyZLHwZNSvCtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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