SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '475137f55451e0a406707671ee31ef24a19928c1092fe5749fd76cc4b507c743' 
  AND token = 'IUXvMhMKKZKH9H0nGD4y4LLnwqaW6mGdTge6e1E5OIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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