SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fa89d9bdfd5ff4e08bca3c593b776c5416deb85defc1f3d42ec80f040153d68' 
  AND token = 's3NoqjeYtLskS1JiAKrX+lVcw8eMU2fwDfmaEgTg5lI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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