SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e119e798f3b179e8e36a913fb562b2ab90dd7f383a8a128201431a714a5f9bb2' 
  AND token = 'HS3QTHOoMxuYRj2r9833Mw2VxOA8uxqmMleXQmbQZeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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