SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c8776b60af22743c6fc4f2b68f11ae44936d58be8c048e1f0a53aa28d50459a' 
  AND token = 'jGP93/A01j+sQoq6zpb9G1y59xzr7jvT9irRgHUvKCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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