SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33163a9068cccc3463841ce63bb9ef0d92cbd7dd9b327a5844f4b6819f31a510' 
  AND token = 'BtzSnGkJ0IYGygPlhFV9utJLZVO1MYsiNE9i2Nq8vI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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