SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6daaf4d8a5b17019eeaea8131f06e796d8ba223a5d40f298b7b54e3083fce5e6' 
  AND token = 'dlz/J+AY26UmY+kZqQjRP7wl0IQzPXSpNufEEe/+RiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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