SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2819d39dc9a1cac0b55c4fde38855ee1a5fa525dc4193a6517af2d91bf1f4b2f' 
  AND token = '/+mwmYIdVx34e0GJuV7RZZ6h4OkzBgodMpuO+0SzG2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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