SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1ff002d3a32fca617b7eba3979e6f0b68a545a79b9b86fa49206e43012563ad' 
  AND token = '5RS+CLFzyVzUKCKRyIxeMtEFxqf2E0AQKIbmz7iwhsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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