SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f791e869ffe9cddd049be94ce8187d142bd9e1df148fee1456fd7796e9e86b52' 
  AND token = 'imvfGIcN2JPf7p/rdFZfUi6nPddpK+SlxFiLTYcuQYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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