SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b5ef2a93fd3935bd5d8a175eb16b932652646a30c5ce95ff2458a8766e12f8' 
  AND token = '4BHk6km4IqlVL5jn5z1QBq1E/nbl5YF88uUvJVyG5Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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