SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '692b1c8b27876638084b46dbf18b252efe47d063d95cfd4133e7e28388834d45' 
  AND token = 'lOGUv/fetmgJXJBkVPSC/xS6KfQJa4MiYGyhokIrWOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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