SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33018db5e4539c47b5fba5161d5332f0450620171929aee91d7e96e339ebbb2b' 
  AND token = '7T+cVzaobYPNq1yZFNnrgdK1fYJM3BDfp9j8vdUVDZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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