SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23e0f53f31b4e39fa373fdc9980cfb0b7b76c51cb6f0fe9682f35a687bf71b2b' 
  AND token = 'sJ2y1akTUlAiIfQVMGAjeZ+sPqUjfrWFTV0XBcU11oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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