SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d2e37013ec1eaebfeed19d53079cb2cda5c5281a8d6e623a9a337b4f9639bdb' 
  AND token = 'kmCHXlBzzBTAaVDYiNIv3NAg7+Ii5tTECIF/jCTETPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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