SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbf21db9bcf4555070be90b70c9b03383ba9f3fd8ba010936236c68e8caa9593' 
  AND token = 'UCuFKKumTFYMDeG5PRvFP1e8uGbDbgP0s1uideQmIvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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