SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ee5eeb40d233cf8507af2f39e3fbf5f77417494ba54830785dab08860718010' 
  AND token = 'ZK0RicX16WialatU4gBMpfDWzufgR7XMNicejHbMAEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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