SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ffe4a6ceaa5d0ef8ebc5a9e51ee8fe8994ced6fc6455be167f332fa8ba1750a' 
  AND token = 'wRHV+oELM/X9I1V/tZcuCQRN9351A2zpM/r3m7Jacf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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