SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c90b35a628c9e09382887fc57626aa0fa4582b431786def6a312bcd1816bdd2' 
  AND token = '6tvAOf7rGXa9arQgShFSmtykinIKkcFGGp3D9rjqy+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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