SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35b9ff659fb0f9505ffefab191fe845ad2cd4c139299b9f8522f98532cc2fe2e' 
  AND token = 'JyQZJIt8WuuVhS8Lbp2Qr1yDsJV7tMdxlpsK3M244U8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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