SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a8623d333af6ad1cfa6d3ba44c87b2497657e1abdb7d82f0c7e6d43b01088b7f' 
  AND token = 'SA8bKl4gufLCcvUxiN994S9/NaX2NTLKKSj1MikTgpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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