SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab497580829de8dfe5588367acc86255420dfd38256dfb80949f12f032b46bf7' 
  AND token = 'dVDmyYxFfiIXuI9JNkJ6x1AhcibwPLUqJnjfHpTciOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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