SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3deb025640f1ebc92206ba244c32dcf30222a9c43fbfce35984c227056cd917e' 
  AND token = 'IIOE0QhFMjQmnWM0bnL7A0F81hgi9vAAjXBvkDt2n8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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