SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0e09686b48a79edeca255adb0493929b042473f1ab6339bab6953a442257490' 
  AND token = 'Zw1DR3C7YABIhy0YHvMLLucxSLnlMRMFznHTmTVbzSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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