SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86a301d3b614248b9f6417e499d12c0d8d5cff278c31563ac083b97fd26e5c8' 
  AND token = 'p+MBckob5TOq+DZBKHybMAghVpQ1di/bstKGtuc3+TA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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