SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5312c9dd818294aa837ea0a1c625ae8706bb7c60322cca0af67881b188d35af4' 
  AND token = 'aPnrTDSBpyHdzdY8VarLRavtFc7gBz8hQJDpTElY6Ak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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