SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd97a80ed383a7c12dd2521e257d676123d68908f3a969d5ccaf5a1375017dcd8' 
  AND token = 'wJmGZESmjLjaRv7VAYBN7EDIsWYaTsZhqcn78NTZk04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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