SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c201f6a567c7fc75c498195f6aeb07fbd4a7ac3bf6d662314b2288d414c26864' 
  AND token = 'crjkZJSQ5nvSWCUs61lTNgI1quf71nj21GfXcLX/s4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}