SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd460b8d33df415466feeb2c081fe4dfe61b8c2ade06e945459519e453c94087b' 
  AND token = '7heM3hQsAVtzUAKbIxbI8IBW+1/KaQzdr+8yM2lWVo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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