SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '529b3ca32cb4d6303ae4f200a720cfa9e03166cfa388825eb7d4be4fb0b3f3ce' 
  AND token = '1DUhMhUEAuCu8LwvzCUN2sezd6hmje9vHmf8mRNL8A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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