SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85a225a36d3bcf546ea1926302e570eff4361dc50b6027e0e586e194d70a268' 
  AND token = '7uSUcNCLf3xGUVEs5v0FbnC+nm8SyOqtzY/SHLMQA/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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