SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2114426538840df8f88541a067d8fb6b4be461dc45c9c4738fb82b9acd9a9b33' 
  AND token = '9tpKm3b5/mBZKsNY+3gHnj5xzaxhBjHwiwWKfnUB5Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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