SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e93e3228286b82fe7680f6e25b2136422e937f4d2f49881f6a32579624d8ab32' 
  AND token = '0+SnrKBmcaqgoysXvmrXdVhNTga35mI9HnGUzXvK4II=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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