SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c106e409357d3d1466a9b0dcfb36782e595e0301bc6a373c96d2393b6b4e7738' 
  AND token = 'eZajRGk+0b2HAdrxsRQHsh0LwJa9OA7ieugBALLkKwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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