SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df46b1df17977d9a0ff576d6d751a4b88a87649c0fb2beee189605c183d9cf1' 
  AND token = 'QfroBUWOFyVLNDRZYikKlIbNT0FhQ9JVMCVxb75YrjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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