SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cf4e9a73c4bf4f4d84da99855603d7ce9a1426b93bc5be7c72af2c18e24e628' 
  AND token = 'rFzwrgGGo7BIjIAhUtID5fNhcfPVWOd0DaurmDAplzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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