SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d3172e411f564c954382d68beb57dd55f33e3d63ba055e26c4d1541b3cdc96e' 
  AND token = 'Bb5+hhjhdEjVGQxRyaKHqZT4Qsz91HulNyXjus7X9iI=' 
  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"
    }
  }
}