SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9efd091ca1f34849ce92fbb573e0a48d364fb8e0583e395d0c3935b721558b48' 
  AND token = 'xshzI2MrIyGDmlG/I2iLRyzJnNRfpSyyqPpichn0IbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}