SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2503b9037bdfa7f1ba562ba763d81833e1f6a14753ca818176b3d7a8a318ab78' 
  AND token = '4mGPjEVRU/nHwv/T2MIy1uTgobIaw78Mi9zfQt8HgTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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