SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb67548edc63fd74926a04020cb0b2058e037e984d5418947e7936f4d6f53727' 
  AND token = '9kfEfGx0msIlXi8VmftXbbN+lbLP6Y3NAkaCklMGXpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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