SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ebbc8cf20367ccbf318c23930ec8dee0ac815124a68a173591e522bf9d95ca' 
  AND token = '/phRe2VSLEiZ39mf4gPGPc7JJskQJuzzgnfBKKkM/2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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