SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3483610639a0780cf76ddb3043746edf53794f20057968dc729a9d239b4a727c' 
  AND token = 'dDpuBx+jU7goSABnht0p7igGGn/gLt6YNKqap1K1TS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}