SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3efccc73512faecf179458899e4ca84e48c78ea2181397a6c98c917d4b4c2590' 
  AND token = 'r9B5Gt8zcy8ax5RUTOToJ4FKZimHnKmrKgePVEsB//c=' 
  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"
    }
  }
}