SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f895211e7b290665f14cac2b81633e6faa2e500e4027ac5ba020da31aa04176a' 
  AND token = 'JN28olSuTBOkopyqvcEIsSjFVP0WqAozau2Ttlnp7n0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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