SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '992b36972772a53a0bfbf2cd6d0cd5e2b4dac31986fee130ea7d8072ab901d87' 
  AND token = 'HsRlqQGUBrZ6h+A1q1RVUcTNHMvYj3sTNXHIbnXAWQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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