SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f78decfacdd1ffb259be33db7f29fc3067d6774155317f080eba61a4b8d5572' 
  AND token = 'lYgtS/ZM9ZduSEKsJYaY3AoMN8/z+OEJ7XRTh6jZrlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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