SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc17e832fa786c30a86a4395cc401acba95d114ef2973873dceea4855657cf93' 
  AND token = 'EQsjOPXCkHxfFGa7hgB3b9bh+DE0eTmg4UNajoZvUbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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